InP nanowire array solar cells achieving 13.8% efficiency by exceeding the ray optics limit

Area of Science:

• Materials Science
• Nanotechnology
• Renewable Energy

Background:

• Planar solar cells face limitations in cost and material usage.
• Nanowire-based photovoltaics offer potential for reduced consumption but struggle with efficiency.

Purpose of the Study:

• To investigate the performance of indium phosphide (InP) nanowire arrays for photovoltaic applications.
• To identify key structural parameters influencing nanowire solar cell efficiency.

Main Methods:

• Fabrication of p-type/intrinsic/n-type (p-i-n) doped InP nanowire arrays.
• Systematic variation of nanowire diameter and n-segment length.
• Characterization of light absorption and carrier collection efficiency.

Main Results:

• Achieved a power conversion efficiency of 13.8%, comparable to record planar InP cells.
• Demonstrated resonant light trapping in 180-nm-diameter nanowires, covering only 12% of the surface.
• Observed a photocurrent conversion share of 71%, significantly exceeding theoretical limits.
• Attained an open-circuit voltage of 0.906 V, surpassing planar InP cells despite a higher surface-to-volume ratio.

Conclusions:

• Nanowire diameter and n-segment length are critical for InP nanowire solar cell performance.
• Optimized nanowire designs enable high efficiency through enhanced light trapping and carrier collection.
• InP nanowire photovoltaics present a promising, material-efficient alternative to planar solar cells.